Treatment for Temporomandibular Disorders (TMD) varies between nonsurgical and surgical interventions. Follow-up studies have shown positive outcomes with either type of intervention. However, due to lack of appropriately designed randomized clinical trials (RCTs), the relative effectiveness of these treatment strategies is not known. This study is the first RCT with an adequate sample size to assess the relative short-term effectiveness of current treatment strategies for subjects with a symptomatic, advanced temporomandibular joint (TMJ) disorder: TMJ disk displacement without reduction with limited mouth opening. This proposal is to continue long-term follow-up of subjects, in this RCT, to evaluate treatment outcomes associated with four treatment strategies for this disorder. These treatment strategies are: Medical Management (Group I), Nonsurgical Rehabilitation (Group II), Arthroscopic Surgery (Group III) and Disk Plication/Repair Surgery (Group IV). Recruitment of subjects is done. Ninety -six subjects have accepted and finished their treatment group assignment. Currently, follow-up exams and questionnaires have been completed at 3, 6, 9, 12, 18, 24, 36, 48 and 60-months post-treatment by 93, 90, 87, 94, 85, 81, 73, 57, and 49 subjects seen currently at each follow-up interval, respectively. The current lost-to-follow-up rate is approximately 15% at 5 years. All subjects will have been in the study at least 2 years at the beginning of this study's proposed funding period. The specific aims of the proposed study is to compare the four treatment strategies according to: 1) an objective measure of jaw function, the Craniomandibular Index (CMI), long-term, at 5 and 10 years, and 2) the subjective perception of pain in the TMJ, measured by applying the Symptom Severity Index to TMJ pain (SSI-JT), long-term, at 3, 4, 5, 6, 7, 8, 9 and 10 years. The primary analyses will compare each of Groups II, III and IV to Group I, to see whether patient outcomes are improved when the initial treatment strategy is more intensive than Group I, that is, medical management. This primary short-term analyses, comparing the CMI and SSI-JT values at 3, 6, 9, 12, 18 and 24 months with patients grouped according to their initial treatment assignment, have found that the other 3 treatment strategies do not improve the outcome, either objectively or subjectively, compared to medical management. Furthermore, relative to the 5 year follow-ups, the conditional power analyses, on the available data for the primary outcome measures, predicts that there is little chance of finding a statistically significant difference between groups at this interval. However, we hold that the 5 years results are not adequate for assessing the lifetime effects of these treatments. Therefore, there is a need to finish long-term follow-up on all currently enrolled subjects to at least 10 years to be able to make definitive conclusions.